This morning I had a problem getting all of my photos off my SD card in a usable format. I used my usual process: take card out of camera, put into card reader, import into lightroom. At the end of the import a message appeared telling me that 36 images were in 'unsupported or damaged".

I can view these images on the camera, but can't view them on my Mac.
In the finder window these 36 images are the only ones that don't have a thumbnail image when looking at the contents of the SD card. I can't view them in Preview, iPhoto or even Nikon Picture Project.

A shell prompt recognises most of my images as "TIFF image data, big-endian" but the "corrupt" ones as "data".
This is the 2nd time this has happened, but this time affects 36 photos so I need to:
a) find a way to get these photos off the card and
b) make sure this never happens again

I decided to head upstairs and grab the direct cable from the box. My reasons for not using this method most of the time is that I prefer the card reader solution because:
a) it doesn't use up the battery
b) the camera isn't lying around on table tops as often and
c) I could actually continue shooting whilst the images get transferred onto the computer.

I plugged in the cable, looked through finder and the 36 troublesome images had icons. With fingers crossed I restarted lightroom and let it start an import. The missing images were all imported. So, it's a card reader problem. The card reader I've been using is a Packard-Bell PB-CR300 and at least one other person has had an issue in the past.

So today I'll be heading off to find a card reader that will work with high speed, high capacity SD cards.